So g4. Classification of building materials according to fire hazard. Flame spread over the surface of building materials

GOST 30244-94 establishes methods for testing building materials for flammability and classifying them according to flammability.

The standard does not apply to varnishes, paints, and other building materials in the form of solutions, powders and granules.

The standard uses the following terms and definitions:

Sustained flaming combustion - continuous flaming combustion of materials for at least 5 s.

Exposed surface - the surface of the sample that is exposed to heat and/or open flame during a flammability test.

Building materials, depending on the values ​​of flammability parameters determined by method I (intended to classify building materials as non-combustible or combustible), are divided into non-combustible and combustible.

Building materials are classified as non-combustible with the following values ​​of flammability parameters:

temperature increase in the furnace is no more than 50°C;

sample weight loss no more than 50%;

Duration of stable flame combustion is no more than 10 s.

Construction materials that do not satisfy at least one of the specified parameter values ​​are classified as flammable.

Combustible building materials, depending on the values ​​of flammability parameters determined by method II (intended for testing combustible building materials in order to determine their flammability groups, are divided into four flammability groups: G1, G2, G3, G4. Materials should be assigned to a certain flammability group when provided that all parameter values ​​set for this group correspond.

Table 3.1

Note. Flammability groups G1 and G2 are equated to the group of low-combustible building materials according to the classification adopted in GOST 12.1.044-89 and SNiP 2.01.02-85*.

Date of publication: 2014-10-30; Read: 1336 | Page copyright infringement

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13 Federal Law dated July 22, 2008 No. 123-FZ

The fire hazard of building materials is characterized by the following properties:

1. flammability;
2. flammability;
3. ability to spread flame over a surface;
4. smoke generating ability;
5. toxicity of combustion products.

Based on flammability, building materials are divided into combustible (G) and non-combustible (NG).

Construction materials are classified as non-combustible with the following values ​​of flammability parameters, determined experimentally: temperature increase - no more than 50 degrees Celsius, sample weight loss - no more than 50 percent, duration of stable flame combustion - no more than 10 seconds.

Construction materials that do not satisfy at least one of the parameter values ​​specified in Part 4 of this article are classified as flammable. Combustible building materials are divided into the following groups:

1) low-flammable (G1), having a flue gas temperature of no more than 135 degrees Celsius, the degree of damage along the length of the test sample is not more than 65 percent, the degree of damage along the mass of the test sample is not more than 20 percent, the duration of independent combustion is 0 seconds;

2) moderately flammable (G2), having a flue gas temperature of no more than 235 degrees Celsius, the degree of damage along the length of the test sample is not more than 85 percent, the degree of damage along the mass of the test sample is not more than 50 percent, the duration of independent combustion is no more than 30 seconds;

3) normal-flammable (NG), having a flue gas temperature of no more than 450 degrees Celsius, the degree of damage along the length of the test sample is more than 85 percent, the degree of damage along the mass of the test sample is not more than 50 percent, the duration of independent combustion is no more than 300 seconds;

4) highly flammable (G4), having a flue gas temperature of more than 450 degrees Celsius, the degree of damage along the length of the test sample is more than 85 percent, the degree of damage along the mass of the test sample is more than 50 percent, and the duration of independent combustion is more than 300 seconds.

For materials belonging to flammability groups G1-GZ, the formation of burning melt drops during testing is not allowed (for materials belonging to flammability groups G1 and G2, the formation of melt drops is not allowed). For non-combustible building materials, other fire hazard indicators are not determined or standardized.

Based on flammability, combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

1) hardly flammable (B1), having a critical surface heat flux density of more than 35 kilowatts per square meter;

2) moderately flammable (B2), having a critical surface heat flux density of at least 20, but not more than 35 kilowatts per square meter;

3) flammable (HF), having a critical surface heat flux density of less than 20 kilowatts per square meter.

According to the speed of flame spread over the surface, combustible building materials (including floor carpets), depending on the value of the critical surface heat flux density, are divided into the following groups:

1) non-propagating (RP1), having a critical surface heat flux density of more than 11 kilowatts per square meter;
2) weakly propagating (RP2), having a critical surface heat flux density of at least 8, but not more than 11 kilowatts per square meter;
3) moderately spreading (RPZ), having a critical surface heat flux density of at least 5, but not more than 8 kilowatts per square meter;
4) highly propagating (RP4), having a critical surface heat flux density of less than 5 kilowatts per square meter.

According to their smoke-generating ability, combustible building materials, depending on the value of the smoke generation coefficient, are divided into the following groups:

1) with low smoke generation capacity (D1), having a smoke generation coefficient of less than 50 square meters per kilogram;
2) with moderate smoke-generating ability (D2), having a smoke generation coefficient of at least 50, but not more than 500 square meters per kilogram;
3) with high smoke-forming capacity (S), having a smoke generation coefficient of more than 500 square meters per kilogram.

Based on the toxicity of combustion products, combustible building materials are divided into the following groups in accordance with Table 2 of the appendix to this Federal Law:
1) low-hazard (T1);
2) moderately dangerous (T2);
3) highly dangerous (HH);
4) extremely dangerous (T4).

Depending on the fire hazard groups, building materials are divided into the following fire hazard classes -

Fire hazard properties of building materials Fire hazard class of building materials depending on groups
materials KM0 KM1 KM2 KM3 KM4 KM5
Flammability NG G1 G1 G2 G2 G4
Flammability - B1 B1 B2 B2 B3
Smoke generating ability - D1 D3+ D3 D3 D3
Toxicity of combustion products - T1 T2 T2 T3 T4
Flame spread over the surface for flooring - RP1 RP1 RP1 RP2 RP4

The flammability group is a conditional characteristic of a certain material, reflecting its ability to burn. In relation to drywall, it is determined by conducting a special flammability test, the conditions of which are regulated by GOST 3024-94. This test is also carried out in relation to other finishing materials, and based on the results of how the material behaves on the test bench, it is assigned one of three flammability groups: G1, G2, G3 or G4.

Is drywall flammable or non-flammable?

All building materials are divided into two main groups: non-combustible (NG) and combustible (G). To qualify as non-combustible, the material must meet a number of requirements that are imposed on it during the testing process. A sheet of drywall is placed in an oven heated to a temperature of about 750 ° C and kept there for 30 minutes. During this time, the sample is monitored and a number of parameters are recorded. Non-combustible material must:

• increase the oven temperature by no more than 50 °C
• give a steady flame for no more than 10 s
• decrease in weight by no more than 50%

Plasterboard sheets do not meet these requirements and are therefore classified in group G (flammable).

Drywall flammability group

Combustible building materials also have their own classification and are divided into four flammability groups: G1, G2, G3 and G4.

The table below illustrates the standards that a material must meet to receive one of the four groups.

The specified parameters refer to samples that have passed the test using Method II, according to GOST 3024-94. This method involves placing the sample in a combustion chamber, in which it is exposed to a flame on one side for 10 minutes so that the temperature in the furnace ranges from 100 to 350 ° C, depending on the distance from the bottom edge of the sample.

In this case, the following characteristics are measured:

• Flue gas temperature
• The time it takes for the flue gases to reach their highest temperature
• Weight of the test sample before and after the test
• Dimensions of damaged surface
• Does the flame spread to that part of the samples that is not heated?
• Duration of burning or smoldering both during heating and after completion of exposure
• Time it takes for the flame to spread to the entire surface
• Does the material burn through?
• Is the material melting?
• Visual change in the appearance of the sample

Having collected and analyzed all the above indicators obtained in laboratory conditions, the material is assigned to one or another flammability group. Based on the figures that were recorded when testing a gypsum board sheet with dimensions of 1000x190x12.5 mm according to Method ll described above, it was found that the flammability group of plasterboard is G1. According to this group, the temperature of its flue gases does not exceed 135 °C, the degree of damage along the length of the sample is no more than 65%, damage by weight is no more than 20%, and the self-combustion time is zero.

Watch a visual process of testing drywall for flammability in the following video:

Fire hazard class

Standard partitions on a metal frame made of plasterboard sheets with an average density of 670 kg/m³ and a thickness of 12.5 mm according to GOST 30403-96 belong to fire hazard class K0 (45). This means that when an unloaded material was exposed to fire for 45 minutes, no vertical or horizontal damage was recorded in it, and there was no combustion or smoke formation.

At the same time, in practice, the load-bearing capacity of a single-layer plasterboard partition is lost after just 20 minutes of fire exposure to the surface of the material. In addition, it should be taken into account that the fire safety of a particular plasterboard partition will depend on its design. Is it installed on a metal frame or on a wooden sheathing, is there a layer of insulation inside and is it flammable?

In addition to fire hazard and flammability, such characteristics as toxicity group of combustion products, smoke-generating ability group and flammability group are also applicable to plasterboard.

In terms of toxicity of combustion products, gypsum plasterboard sheets are classified as low-hazard (T1). The smoke-forming ability of a material characterizes it as having a low smoke-forming ability (D1) with a smoke generation coefficient of no more than 50 m²/kg (smoke optical density). For comparison, wood during smoldering has a value of this coefficient equal to 345 m²/kg. Flammability group for plasterboard B2 - moderately flammable materials.

Read also:

Fire-technical classification of building materials, structures, premises, buildings, elements and parts of buildings is based on their division according to properties that contribute to the occurrence of dangerous fire factors and its development - fire danger, and according to the properties of resistance to the effects of fire and the spread of its dangerous factors - fire resistance.

CONSTRUCTION MATERIALS

Building materials are characterized only by fire hazard.
The fire hazard of building materials is determined by the following fire-technical characteristics: flammability, flammability, flame spread over the surface, smoke-generating ability and toxicity.

Flammability of building materials.

Construction materials are divided into non-flammable (NG) And flammable (G). Combustible building materials are divided into four groups:

• G1(low flammability);
• G2(moderately flammable);
• G3(normally flammable);
• G4(highly flammable).

Flammability and flammability groups of building materials are established according to GOST 30244.

Flammability of building materials.

Combustible building materials are divided into three groups based on flammability:

• IN 1(flammable);
• AT 2(moderately flammable);
• AT 3(highly flammable).

Flammability groups of building materials are established according to GOST 30402.

Spread of flame over the surface of building materials.

Combustible building materials are divided into four groups according to the spread of flame over the surface:

• RP1(non-proliferating);
• RP2(low spreading);
• RP3(moderately spreading);
• RP4(highly spreading).

Groups of building materials for flame propagation are established for the surface layers of roofs and floors, including carpets, in accordance with GOST 30444 (GOST R 51032-97).

Smoke-forming ability of building materials.

Combustible building materials are divided into three groups according to their smoke-generating ability:

• D1(with low smoke-generating ability);
• D 2(with moderate smoke-generating ability);
• DZ(with high smoke-generating ability).

Groups of building materials according to smoke-generating ability are established according to GOST 12.1.044.

Toxicity of building materials.

Combustible building materials are divided into four groups based on the toxicity of combustion products:

• T1(low hazard);
• T2(moderately dangerous);
• TK(highly dangerous);
• T4(extremely dangerous).

Groups of building materials based on the toxicity of combustion products are established according to GOST 12.1.044.

BUILDING CONSTRUCTION

Building structures are characterized by fire resistance and fire hazard.
The fire resistance indicator is fire resistance limit, the fire hazard of a structure is characterized by Class her fire danger.

Fire resistance limit of building structures.

The fire resistance limit of building structures is established by the time (in minutes) of the onset of one or sequentially several signs of limit states, standardized for a given structure:

• loss of bearing capacity (R);
• loss of integrity (E);
• loss of thermal insulation ability (I).

The fire resistance limits of building structures and their symbols are established in accordance with GOST 30247.

In this case, the fire resistance limit of windows is established only by the time of loss of integrity (E).

Fire hazard class of building structures.

Based on fire hazard, building structures are divided into four classes:

• KO(non-fire hazardous);
• K1(low fire hazard);
• K2(moderate fire hazard);
• short circuit(fire hazardous).

The fire hazard class of building structures is established according to GOST 30403.

The Technical Code of Standard Practice establishes the fire-technical classification of building materials, products, structures, buildings and their elements. This regulatory act regulates the classification of materials, products and structures by fire hazard depending on fire-technical characteristics, as well as determination methods.

The fire hazard of building materials is determined by the following fire-technical characteristics or their combination:

Flammability;

Flammability;

Spread of flame over the surface;

Toxicity of combustion products;

Smoke generating ability.

Building materials, depending on the values ​​of flammability parameters determined according to GOST 30244, are divided into non-combustible
and flammable. For building materials containing only inorganic (non-flammable) components, the characteristic is “flammability”
not determined.

Combustible building materials are divided depending on:

1. Values ​​of flammability parameters determined according to GOST 30244 into flammability groups:

G1, slightly flammable;

G2, moderately flammable;

G3, normally flammable;

G4, highly flammable.

2. Values ​​of critical surface heat flux density according to GOST 30402 for flammability groups:

B1, flame retardant;

B2, moderately flammable;

B3, highly flammable.

3. B values ​​of critical surface heat flux density according to GOST 30444 into groups for flame propagation:

RP1, non-distributing;

RP2, weakly spreading;

RP3, moderately spreading;

RP4, highly spreading.

4. Lethal effect of gaseous combustion products from the mass of material per unit volume of the exposure chamber
according to GOST 12.1.044 into groups according to the toxicity of combustion products:

T1, low hazard;

T2, moderately dangerous;

T3, highly hazardous;

T4, extremely dangerous.

4. Values ​​of the smoke generation coefficient according to GOST 12.1.044 into groups according to smoke generation ability:

D1, with low smoke-generating ability;

D2, with moderate smoke-generating ability;

D3, with high smoke-generating ability.

Flammability group– this is a classification characteristic of the ability of substances and materials to.

When determining the fire and explosion hazard of substances and materials (), there are :

• gases– these are substances whose saturated vapor pressure at a temperature of 25 °C and a pressure of 101.3 kPa exceeds 101.3 kPa;
• liquids– these are substances whose saturated vapor pressure at a temperature of 25 °C and a pressure of 101.3 kPa is less than 101.3 kPa. Liquids also include solid melting substances whose melting or dropping point is less than 50 °C.
• solids and materials– these are individual substances and their mixed compositions with a melting or dropping point greater than 50 ° C, as well as substances that do not have a melting point (for example, wood, fabrics, etc.).
• dust– These are dispersed solids and materials with a particle size of less than 850 microns.

One of the indicators of fire and explosion hazard of substances and materials is flammability group.

Substances and materials

According to GOST 12.1.044-89, in terms of flammability, substances and materials are divided into the following groups ( excluding construction, textile and leather materials):

1. Non-flammable.
2. Low-flammability.
3. Flammable.

Non-flammable – these are substances and materials that are unable to burn in air. Non-flammable substances can be fire-explosive (for example, oxidizers or substances that release flammable products when interacting with water, atmospheric oxygen, or with each other).

Low-flammability – these are substances and materials that can burn in air when exposed to an ignition source, but are unable to burn independently after it is removed.

Flammable – these are substances and materials that can spontaneously ignite, as well as ignite when exposed to an ignition source and burn independently after its removal.

The essence of the experimental method for determining flammability is to create temperature conditions conducive to combustion and assess the behavior of the substances and materials under study under these conditions.

Solid (including dust)

The material is classified as non-flammable if the following conditions are met:

• the arithmetic mean change in temperature in the oven, on the surface and inside the sample does not exceed 50 °C;
• the arithmetic mean value of mass loss for five samples does not exceed 50% of their mean value of the initial mass after conditioning;
• the arithmetic mean value of the duration of stable combustion of five samples does not exceed 10 s. The test results of five samples in which the duration of stable combustion is less than 10 s are taken equal to zero.

Based on the value of the maximum temperature increase (Δt max) and mass loss (Δm), materials are classified:

• flame retardant: Δt max< 60 °С и Δm < 60%;
• flammable: Δt max ≥ 60 °C or Δm ≥ 60%.

Combustible materials are divided depending on the time (τ) to reach (t max) into:

• hardly flammable: τ > 4 min;
• average flammability: 0.5 ≤ τ ≤ 4 min;
• flammable: τ< 0,5 мин.

Gases

If there are concentration limits for flame propagation, the gas is classified as flammable ; in the absence of concentration limits for flame propagation and the presence of a self-ignition temperature, the gas is classified as flame retardant ; in the absence of concentration limits for flame propagation and auto-ignition temperature, the gas is classified as non-flammable .

Liquids

If there is an ignition temperature, the liquid is classified as flammable ; in the absence of an ignition temperature and the presence of a self-ignition temperature, the liquid is classified as flame retardant . In the absence of flash points, ignition, self-ignition, temperature and concentration limits for flame propagation, the liquid is classified as non-flammable . Flammable liquids with a flash point of not more than 61 ° C in a closed crucible or 66 ° C in an open crucible, phlegmatized mixtures that do not have a flash in a closed crucible are classified as flammable . Particularly dangerous These are flammable liquids with a flash point of no more than 28 °C.

Classification of building materials

Determination of the flammability group of a building material

The fire hazard of building, textile and leather materials is characterized by the following properties:

1. The ability to spread flame over a surface.
2. Smoke generating ability.
3. Toxicity of combustion products.

Building materials, depending on the values ​​of flammability parameters, are divided into groups into non-combustible and combustible (for floor carpets the flammability group is not determined).

NG (non-flammable)

Based on test results using methods I and IV (), non-combustible building materials are divided into 2 groups.

Construction materials are classified as non-combustible group I

• temperature increase in the oven no more than 30 °C;
• duration of stable flame combustion – 0 s;
• calorific value not more than 2.0 MJ/kg.

Construction materials are classified as non-combustible group II with the following arithmetic average values ​​of flammability parameters according to methods I and IV (GOST R 57270-2016):

• temperature increase in the oven no more than 50 °C;
• weight loss of samples no more than 50%;
• the duration of stable flame combustion is no more than 20 s;
• calorific value not more than 3.0 MJ/kg.

Allowed to be classified as non-flammable of group I without testing the following building materials without painting their outer surface or with painting the outer surface with compositions without the use of polymer and (or) organic components:

• concrete, mortars, plasters, adhesives and putties, clay, ceramic, porcelain stoneware and silicate products (bricks, stones, blocks, slabs, panels, etc.), fiber cement products (sheets, panels, slabs, pipes, etc. .) with the exception in all cases of materials manufactured using polymer and (or) organic binder fillers and fiber;
• inorganic glass products;
• products made from alloys of steel, copper and aluminum.

Building materials that do not satisfy at least one of the above specified values ​​of parameters of I and II groups of non-combustibility belong to the group of combustibles and are subject to testing according to methods II and III (GOST R 57270-2016). For non-combustible building materials, other fire hazard indicators are not determined or standardized.

Combustible building materials, depending on the values ​​of flammability parameters determined by method II, are divided into four flammability groups (G1, G2, G3, G4) in accordance with the table. Materials should be classified into a certain flammability group provided that all arithmetic mean values ​​of the parameters specified in the table for this group correspond.

G1 (low flammable)

Low flammable – these are materials with a flue gas temperature of no more than 135 °C, the degree of damage along the length of the test sample is not more than 65%, the degree of damage along the mass of the test sample is not more than 20%, and the duration of spontaneous combustion is 0 seconds.

G2 (moderately flammable)

Moderately flammable – these are materials with a flue gas temperature of no more than 235 °C, the degree of damage along the length of the test sample is no more than 85%, the degree of damage along the mass of the test sample is no more than 50%, and the duration of independent combustion is no more than 30 seconds.

G3 (normally flammable)

Normally flammable – these are materials with a flue gas temperature of no more than 450 °C, a degree of damage along the length of the test sample of more than 85%, a degree of damage along the mass of the test sample of no more than 50%, and a duration of independent combustion of no more than 300 seconds.

G4 (highly flammable)

Highly flammable – these are materials with a flue gas temperature of more than 450 °C, a degree of damage along the length of the test sample of more than 85%, a degree of damage along the mass of the test sample of more than 50%, and a duration of independent combustion of more than 300 seconds.

Table

Video, what is a flammability group

Sources: ; Baratov A.N. Combustion – Fire – Explosion – Safety. -M.: 2003; GOST 12.1.044-89 (ISO 4589-84) System of occupational safety standards. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination; GOST R 57270-2016 Construction materials. Combustibility test methods.

Flammability is the ability of substances and materials to ignite.

Federal Law No. 123-FZ of July 22, 2008 “Technical Regulations on Fire Safety Requirements” defines general requirements that determine the possibility of using building and finishing materials depending on their flammability rating.

The flammability index is also taken into account when choosing materials for finishing floors, walls and ceilings along escape routes in buildings.

The essence of the method for determining the flammability of a material is to determine the parameters of the flammability of the material at the levels specified by the standard of exposure to the surface of the test sample of radiant heat flux and flame from the ignition source.

The parameters of the flammability of a material are the critical surface heat flux density (CSHDD) and the ignition time.

To classify materials into flammability groups, KPPTP (the minimum value of surface heat flux density at which stable flame combustion occurs) is used.

Combustible building materials (according to GOST 30244), depending on the value of the KPPTP (the minimum value of the surface heat flux density at which stable flaming combustion occurs), are divided into three flammability groups: B1, B2, B3.

To conduct tests at the Federal State Budgetary Institution SEU FPS IPL in the Republic of Mordovia, it is necessary to provide 15 square-shaped samples with sides of 165 mm and a deviation of minus 5 mm. The thickness of the samples should be no more than 70 mm. For each value of surface heat flux density (SHHD), tests are carried out on three samples.

When making samples, the exposed surface should not be processed.

If there are corrugations, relief, embossing, etc. on the exposed surface. The size of the protrusions (depressions) should be no more than 5 mm.

If the exposed surface does not meet the specified requirements, it is allowed to make samples for testing from a material with a flat surface, i.e. without corrugations, relief, embossing, etc.

Samples for standard testing of materials used only as finishing and facing materials, as well as for testing paint coatings and roofing materials, are made in combination with a non-combustible base. The fastening method must ensure tight contact between the surfaces of the material and the base.

As a non-combustible base, asbestos-cement sheets should be used in accordance with GOST 18124 with a thickness of 10 or 12 mm.

In cases where specific technical documentation does not provide conditions for standard testing, samples are made with the base and fastening specified in the technical documentation.

For layered materials with different surface layers, two sets of samples are made to expose both surfaces. In this case, the flammability group of the material is determined based on the worst result.

Testing of samples is carried out in a thermophysical laboratory at the Flammability testing facility.

Installation diagram for determining the flammability of materials. 1 - radiation panel with heating element; 2 - movable burner; 3 - auxiliary stationary burner; 4 - power cable of the heating element; 5 - cam with a stroke limiter for manual control of the movable burner; 6 - cam for automatic control of the movable burner; 7 - drive belt; 8 — bushing for connecting the movable burner to the fuel supply system; 9 — mounting plate for the ignition system and the movable burner movement system; 10 — protective plate; 11 — vertical support; 12 — vertical guide; 13 - movable platform for the sample; 14 — base of the support frame; 15 — manual control; 16 — lever with counterweight; 17 - drive to the electric motor.

Installation type “Flammability”

The results are processed according to the GOST 30402-96 methodology. For each tested sample, the ignition time and the following additional observations are recorded: time and place of ignition; the process of sample destruction under the influence of thermal radiation and flame; melting, swelling, delamination, cracking, swelling or shrinkage.

After testing and payment of the test cost, fire testing laboratory employees prepare reporting documentation.

Related Posts

It is determined by the following fire-technical characteristics: flammability, flame spread over the surface, flammability, smoke-generating ability, toxicity of combustion products. These indicators establish a range of fire hazard indicators for fire retardant compounds to determine their scope of application in the construction and decoration of buildings and premises.

Flammability

Building materials are divided into non-combustible (NG) and combustible (G). Treated materials can have one of 4 groups: G1 - low-flammable, G2 - moderately flammable, G3 - normally flammable, G4 - highly flammable.
Flammability and flammability groups are established according to GOST 30244-94.

To carry out the flammability test, 4 samples are taken - boards treated with a fire retardant compound. A box is built from these samples. It is placed in a chamber in which 4 gas burners are located. The burners are ignited in such a way that the flame acts on the lower surface of the samples. At the end of combustion, the following are measured: the temperature of the exhaust flue gases, the length of the damaged section of the sample, mass, and residual combustion time. Having analyzed these indicators, wood treated with a fire retardant composition is classified into one of four groups.

Flame Spread

Combustible building materials are divided into 4 groups based on the spread of flame over the surface: RP1 - non-propagating, RP2 - weakly spreading, RP3 - moderately spreading, RP4 - highly spreading.

GOST R 51032-97 regulates testing methods for building materials (including those treated with fire retardants) for flame propagation. To carry out testing, the sample is exposed to the heat of a radiation panel located at a slight angle and heated to a certain temperature. Depending on the heat flux density, the value of which is determined by the length of flame propagation along the sample, the material treated with a fire retardant composition is assigned to one of four groups.

Flammability

Combustible building materials are divided into groups according to flammability: B1 – hardly flammable, B2 – moderately flammable, B3 – highly flammable.

GOST 30402 defines methods for testing building materials for flammability. The group is determined depending on the heat flux of the radiation panel at which ignition occurs.

Smoke generating ability

According to this indicator, materials are divided into 3 groups: D1 - with low smoke-generating ability, D2 - with moderate smoke-generating ability, D3 - with high smoke-generating ability.
Smoke generating ability groups are established according to GOST 12.1.044. For testing, the sample is placed in a special chamber and burned. During combustion, the optical density of the smoke is measured. Depending on this indicator, wood with a fire retardant applied to it is classified into one of three groups.

Toxicity

Based on the toxicity of combustion products, there are 4 groups of materials: T1 - low-hazardous, T2 - moderately hazardous, T3 - highly hazardous, T4 - extremely hazardous. Toxicity groups are established according to GOST 12.1.044.

9.1. The test specimen, conditioned in accordance with 6.7, is wrapped in a sheet of aluminum foil (nominal thickness 0,2 mm) with a hole 140 mm in diameter cut in the center. In this case, the center of the hole in the foil must coincide with the center of the exposed surface of the sample (Figure A14).

9.2. The test sample is placed in a holder, placed on a movable platform and the counterweight is adjusted. After this, the holder with the test sample is replaced with a holder with a simulator sample.

9.3. Set the movable burner to its original position according to 7.4.1, regulate the gas flow (19 - 20 ml/min) and air (160 - 180 ml/min) supplied to the movable burner. For the auxiliary burner, the flame length is approximately 15 mm.

9.4. Turn on the power supply and use the regulating thermoelectric converter to set the thermoEMF value set during calibration, corresponding to a PPTP of 30 kW/m 2 .

9.5. After reaching the specified thermoEMF value, the installation is kept in this mode for at least 5 minutes. In this case, the thermoEMF value recorded by the controlling thermoelectric converter should differ from that obtained during calibration by no more than 1%.

9.6. Place the shielding plate on the protective plate, replace the simulator sample with the test specimen, turn on the movable burner mechanism, remove the shielding plate and turn on the time recorder.

The time required to carry out these operations should be no more than 15 seconds.

9.7. After 15 minutes or when the sample ignites, the test is stopped. To do this, place the shielding plate on the protective plate, stop the time recorder and the movable burner mechanism, remove the holder with the sample and place the simulator sample on the movable platform, remove the shielding plate.

9.8. The PPTP value is set to 20 kW/m2 if ignition was recorded in the previous test, or 40 kW/m2 if it was absent. Repeat operations according to 9.5 - 9.7.

9.9. If ignition is detected at an PPTP of 20 kW/m 2, reduce the PPTP value to 10 kW/m 2 and repeat operations in 9.5 - 9.7.

9.10. If there is no ignition at an PPTP of 40 kW/m2, set the PPTP value to 50 kW/m2 and repeat operations in 9.5 - 9.7.

9.11. After determining two values ​​of PPTP, at one of which ignition is observed, and at the other - no ignition, set the PPTP value to 5 kW/m 2 greater than the value at which there is no ignition, and repeat operations according to 9.5 - 9.7 on three samples.

If ignition is detected at an PPTP of 10 kW/m 2, then the next test is carried out at a PPTP of 5 kW/m 2.

9.12. Depending on the test results according to 9.11, the PPTP value is increased by 5 kW/m2 (in the absence of ignition) or reduced by 5 kW/m2 (in the presence of ignition) and the operations in 9.5 - 9.7 are repeated on two samples.

9.13. For each tested sample, record the ignition time and the following additional observations: time and place of ignition; the process of sample destruction under the influence of thermal radiation and flame; melting, swelling, delamination, cracking, swelling or shrinkage.

9.14. For materials with high compressibility (mineral wool boards), as well as materials that melt or soften during heating, the test should be carried out taking into account 7.2.7.

9.15. For materials that acquire the ability to stick when heated, or form a surface charred layer with low mechanical strength, or contain an air gap under the exposed surface, in order to prevent interference with the movement of the movable burner or damage by the burner to the exposed surface of the sample, tests should be carried out using a stopper in the drive mechanism, eliminating the possibility of contact of the movable burner with the surface of the sample.

9.16. For materials that generate a significant amount of smoke or decomposition products that extinguish the flame of the moving burner and exclude the possibility of its re-ignition using an auxiliary burner, the result is recorded in the test report indicating the absence of ignition due to the systematic extinguishing of the flame of the moving burner by decomposition products.